1. Field of the Invention
The present invention relates to a double window/door system for blocking infrared rays, and more particularly, to a double window/door system for blocking infrared rays, thereby increasing the degree of blocking infrared rays in glass of a dual structured window, to save energy required for cooling and heating in a room.
2. Description of the Related Art
In conventional windows and doors of most dwellings and buildings, the insulation is very weak so that 45% or more of the heat energy in the structures is lost through the windows and doors.
To reduce heat loss, multiple panes of glass have been arranged in the forms of double panes and triple panes by using a method of connecting multiple layers of glass. Multiple panes of glass are manufactured by positioning a spacer to keep space between a pair of panes, applying an adhesive, such as butyl rubber, on both sides of the spacer and then applying predetermined pressure and heat in a vacuum so that the panes are glued to the both sides of the spacer. These multiple panes of glass are effective in soundproofing and insulating due to the vacuum formed between the panes and therefore these are widely used as building materials.
In the constitution of multiple panes of glass, ordinary glass is used for the panes or low-E glass (low-emissivity glass) and ordinary glass are used for the panes. Low-E glass is similar to ordinary glass in transmittance. Ordinary glass reflects only a part of infrared rays. To improve the insulation of a building, low-E glass is formed by coating the inside of ordinary glass with a special metal film [generally, silver (Ag)] having a high ratio of reflecting infrared rays. Since the special metal film of low-E glass transmits visible light to improve lighting inside and it reflects infrared rays to minimize heat transfer between inside and outside, low-E glass is energy saving glass making the change in the inside temperature small. Based on a coating manufacturing method, low-E glass is classified into hard low-E glass by a pyrolytic process and soft low-E glass by a sputtering process.
Low-E glass has differences according to usage conditions. However, low-E glass has an energy saving effect of about 50% in comparison with a single pane of glass and an energy saving effect of about 25% in comparison with ordinary multiple panes of glass. Due to these merits, low-E glass is used for windows or lighting in homes and general buildings and it is used for energy saving. Specifically, low-E glass is proper for hospitals, hotels, etc. wherein heating/cooling systems are operated for 24 hours.
However, when low-E glass is used in each pane to better block infrared rays as illustrated in FIG. 1, the reduction extent of infrared rays by the double panes of low-E glass is not doubled, as desired, compared with the reduction extent of infrared rays by a single pane of low-E glass. Moreover, the transmittance of visible light significantly drops to make the inside dark. Thus, there is a problem in using double panes of low-E glass for ordinary windows or doors.
When double panes of low-E glass are used, an inactivate gas is introduced between the panes, thereby partially decreasing heat rays/infrared rays. However, a small glass manufacturer having no special equipment cannot easily perform this re-processing work.